The present invention relates to a storage apparatus, a method for validating encrypted content and a terminal apparatus, and more particularly, to a method for validating encrypted content to make watching-restricted content watchable, a storage apparatus for storing encrypted content, and a terminal apparatus for watching encrypted content in a storage apparatus.
Recently, a digital information processing technology or a telecommunication technology rapidly develops, and a storage apparatuses such as a hard disc drive (HDD) and a digital video disc (DVD) are developing with a trend of a large capacity and high performance. As transmission means becomes diverse and advanced, a large quantity of digital contents are distributed to users through a network or a storage medium, and users can more easily enjoy digital contents. To the contrary, due to unauthorized uses of digital content such as an illegal copy or unauthorized modification, a copyright of a copyright holder is increasingly infringed.
In order to address the above problem, various technologies for protecting a copyright of a copyright holder while securing convenience of a user and a service or a system based on them have been introduced. For example, as a related art related to an on-line rental service of digital content, a technology disclosed in Patent Document 1 (Japanese Patent Laid-Open Publication No. 2002-42234) is known.
In Patent Document 1, a user registers information such as a user name or a credit card to a rental server, and when a rental request of content is received from a user terminal, a rental server performs user authentication and issues encrypted content and a decryption key (electronic ticket) for decrypting encrypted content, and a user watches encrypted content by using them. Also, in Patent Document 1, a user does not upload downloaded data in order to return content and instead returns the electronic ticket to the rental server.
In Patent Document 1, if the electronic ticket is returned, encrypted content stored in a user terminal can not be watched, and so it is possible to efficiently prevent unauthorized watching of content and an illegal copy of content.
As another related art, for example, a technology disclosed in Patent Document 2 (Japanese Patent Laid-Open Publication No. H11-283327) is known. In Patent Document 2, a service provider first distributes a DVD storing encrypted content to a user, and a user then purchases a license containing a content key for decrypting encrypted content from a license server to which a user has previously registered as a membership and decrypts encrypted content by using the key to watch it.
Also, Patent Document 2 suggests a service that a user first purchases points used to watch content, and points are then used to use and exchange content.